A dilapidated building and another under construction collapsed in India on Saturday, killing at least 19 people as rescuers searched for dozens of others feared trapped, police and fire officials said.

In New Delhi, a four-story 50-year-old structure toppled in an area inhabited by the poor. The collapse killed at least 11 people and one survivor was being treated in a hospital, said fire service officer Praveer Haldiar.

Hours later, a 12-story building under construction collapsed on the outskirts of Chennai, the capital of southern Tamil Nadu state, as heavy rains pounded the area.

Police said 26 construction workers had been pulled out and the search was continuing for a dozen others. Eight of them died, said police officer Mansur Ali.

Nearly 300 policemen and fire service workers were working through Saturday night, scouring the debris for survivors.

Most homes in the New Delhi area where the first building collapsed had been built without permission and using substandard materials, police officer Madhur Verma said.

The Press Trust of India news agency said the New Delhi collapse was triggered by construction work on an adjacent plot.

Building collapses are common in India, where high demand for housing and lax regulations have encouraged some builders to cut corners, use substandard materials or add unauthorized extra floors.